Larval Development of the Shorthead Redhorse (Moxostoma macrolepidotum) from the Susquehanna River
- 1 March 1979
- journal article
- research article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 108 (2) , 161-165
- https://doi.org/10.1577/1548-8659(1979)108<161:ldotsr>2.0.co;2
Abstract
Shorthead redhorse eggs hatched 8 days after fertilization at a mean temperature of 15.6.degree. C. The total length (TL) of newly hatched larvae averaged 10.0 mm (range, 9.3-10.4 mm); their standard (notochord) length averaged 9.4 mm (range 8.7-9.9 mm). They were melanophore-free, had slightly upturned urostyles and incomplete mouths. Melanophores appeared for the 1st time in larvae of 10.2 mm TL. Fin rays were visible in caudal, dorsal, pectoral, anal and pelvic fins by 12.9, 15.8, 16.0, 16.7 and 18.8 mm TL, respectively. Transformation of shorthead redhorse to the mesolarval phase occurred by 12.4 mm TL and to metalarval phase by 16.2 mm TL. Protolarvae of the shorthead redhorse are distinguished from those of northern hog sucker (Hypentelium nigricans) from the Susquehanna River by their smaller standard (notochord) length and larger postanal length as percentages of TL and their fewer preanal myomeres. Shorthead redhorse mesolarvae lack the melanophore-free area between the eyes found in northern hog suckers and have sparser dorsal body pigmentation but denser pigmentation along the lateral line area than have mesolarvae of northern hog suckers. Metalarvae of the 2 species are distinguished by pigmentation patterns.Keywords
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